Adams谱序列上的非平凡乘积b_0k_0δ_(s+4)

主要用May谱序列证明了非平凡的乘积b_0k_0δ_(s+4)∈Ext_A~(s+8,t)(Z_p,Z_p),其中p是大于等于7的素数,0≤sp-4,q=2(p-1),t=(s+4)p~3q+(s+3)p~2q+(s+5)pq+(s+2)q+s.     

Synthesis and Crystal Structure of a Novel Binuclear Copper(Ⅱ)Complex,[Cu(paba)C1]

A novel binuclear Cu(Ⅱ)complex[Cu(paba)C1](pabaH=2-(2-pyridylmethylimine)benzenesulfonic acid)has been synthesized and characterized by elemental analysis,IR andsingle-crystal X-ray diffraction.The crystal of the title complex crystallizes in a monoclinie system,space group P21/n,with a=6.8165(7),b=15.3073(16),c=12.3795(13)(A),β=95.0160(10)°,V=1286.8(2)(A)3,Mr=360.26,Dc=1.860 g/cm3,μ=2.074 mm-1,F(000)=724,Z=4,the final R=0.0252 and wR=0.0675 for 2395 observed reflections with I＞2σ(I).The title complex is centrosymmetric and a pair of chlorides act as μ2-bridges to link two Cu(Ⅱ)ions forming a binuclear complex.Every Cu(Ⅱ)ion is five-coordinated by pyridyl N,imine N and sulfonate O atoms of the tridentate paba ligand as well as two bridging Cl-,constructing the distorted square-pyramidal geometry.In the structure extensive hydrogen bonds and weak π-π stacking stabilize the solid structures,through which the complex builds its 3-dimensional supramolecular structure.     

On the iterates of positive linear operators preserving the affine functions

In this note we study the limit behavior of the iterates of a large class of positive linear operators preserving the affine functions and, as a byproduct of our result, we obtain the limit of the iterates of Meyer-König and Zeller operators.     

Four Families of Nontrivial Product Elements in the Stable Homotopy Groups of Spheres

In this paper, the authors introduce a new effective method to compute the generators of the E1-term of the May spectral sequence. This helps them to obtain four families of non-trivial product elements in the stable homotopy groups of spheres.     

球面稳定同伦群中第三周期γ类非平凡新元素

本文研究了球面稳定同伦群的问题.以Adams谱序列中的第二非平凡微分为几何输入,给出了球面稳定同伦群中h₀g_n（n > 3）的收敛性.同时,由Yoneda乘积的知识,发掘了球面稳定同伦群中的一个非平凡新元素.非平凡元素的范围将被我们的结果进一步扩大.     

Hyperbolic Wavelet Approximation

We study the multivariate approximation by certain partial sums (hyperbolic wavelet sums) of wavelet bases formed by tensor products of univariate wavelets. We characterize spaces of functions which have a prescribed approximation error by hyperbolic wavelet sums in terms of a K -functional and interpolation spaces. The results parallel those for hyperbolic trigonometric cross approximation of periodic functions [DPT]. October 16, 1995. Date revised: August 28, 1996.     

On Measures Induced by Extremal Signatures in Best Real Polynomial Approximation

We consider the limit distribution of measures μ _n , that appear in extremal signatures in the best polynomial approximation of a real-valued function . Relations between structural properties of the function f and weak-star limit points of (μ _n ) _n are proved. April 4, 1996. Date revised: October 25, 1996.     

A Four-filtrated may spectral sequence and its applications

In this paper, we introduce a four-filtrated version of the May spectral sequence (MSS), from which we study the general properties of the spectral sequence and give a collapse theorem. We also give an efficient method to detect generators of May E ₁-term E ₁ ^s,t,b,* for a given (s, t, b, *). As an application, we give a method to prove the non-triviality of some compositions of the known homotopy elements in the classical Adams spectral sequence (ASS). This research is partially supported by the National Natural Science Foundation of China (Nos. 10501045, 10771105) and the Fund of the Personnel Division of Nankai University     

A nontrivial product in the stable homotopy groups of spheres

Let A be the mod p Steenrod algebra for p an arbitrary odd prime. In 1962, Li-uleviciusdescribed hi and bk in Ext (A|*,*) (Zp, Zp) having bigrading (1,2pi(p-1))and (2,2pk+1 x(p - 1)), respectively. In this paper we prove that for p ≥ 7,n ≥ 4 and 3 ≤ s < p - 1, (Zp,Zp) survives to E∞ in the Adams spectral sequence, where q = 2(p - 1).     

On the Asymptotically Optimal Rate of Approximation of Multiplier Operators from L p into L q

The asymptotic behavior of the n -widths of multiplier operators from L _p [0,1] into L _q [0,1] is studied. General upper and lower bounds for the n -widths in terms of the multipliers are established. Moreover, it is shown that these upper and lower bounds coincide for some important concrete examples. August 3, 1994. Date revised: November 15, 1996.